OBJECTIVE: To investigate the intake of iodine in mother-infant pairs. DESIGN: An exploratory, cross-sectional study. Iodine intake was estimated using Nutritics nutritional analysis software, following 24-hour dietary recall. Iodine-rich foods were grouped and compared between those women who met the UK RNI for iodine (140 µg/day) and those who did not. SETTING: Online and telephone questionnaires. PARTICIPANTS: Self-selecting caregivers of infants aged 6-12 months. RESULTS: Ninety-one mother-infant pairs with a mean (SD) age of 33.2 (4.1) years and 8.4 (1.3) months, respectively, were included. Most mothers were exclusively breast feeding (54.9%). The estimated maternal median iodine intake from food and supplements (median 140.3 µg/day, just meeting the UK RNI for women of reproductive age, but not the WHO or BDA recommendations for lactating women (250 µg/day and 200 µg/day, respectively). Forty-six (50.5%) of mothers met the UK RNI. Estimated intakes of fish, eggs, cow's milk, and yoghurt/cream/dairy desserts were significantly greater, whilst intakes of plant-based milk alternative drinks were significantly less in mothers who met the RNI for iodine (P<
0.05) compared with those who did not. Infant iodine intake from food was positively correlated with maternal
total iodine intake, iodine intake from all food, and iodine intake from dairy foods (Spearman's rho=0.243, 0.238, 0.264 respectively
P<
0.05). CONCLUSIONS: Women in the UK may not consume enough iodine to meet the demands of lactation. Guidance on iodine-containing foods, focussed on intake before and during pregnancy and lactation, and mandatory fortification of plant-based milk-alternatives could all serve to avoid deficiency.